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108 lines
3.2 KiB
C
108 lines
3.2 KiB
C
/*-
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* Copyright (c) 2003 David Schultz <das@FreeBSD.ORG>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <float.h>
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#include <inttypes.h>
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#include <limits.h>
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#include <math.h>
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#include <stdlib.h>
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#include "fpmath.h"
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#include "gdtoaimp.h"
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/*
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* ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(),
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* except that the floating point argument is passed by reference.
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* When dtoa() is passed a NaN or infinity, it sets expt to 9999.
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* However, a long double could have a valid exponent of 9999, so we
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* use INT_MAX in ldtoa() instead.
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*/
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char *
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__ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign,
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char **rve)
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{
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FPI fpi = {
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LDBL_MANT_DIG, /* nbits */
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LDBL_MIN_EXP - LDBL_MANT_DIG, /* emin */
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LDBL_MAX_EXP - LDBL_MANT_DIG, /* emax */
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FLT_ROUNDS, /* rounding */
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#ifdef Sudden_Underflow /* unused, but correct anyway */
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1
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#else
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0
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#endif
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};
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int be, kind;
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char *ret;
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union IEEEl2bits u;
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uint32_t bits[(LDBL_MANT_DIG + 31) / 32];
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void *vbits = bits;
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u.e = *ld;
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/*
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* gdtoa doesn't know anything about the sign of the number, so
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* if the number is negative, we need to swap rounding modes of
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* 2 (upwards) and 3 (downwards).
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*/
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*sign = u.bits.sign;
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fpi.rounding ^= (fpi.rounding >> 1) & u.bits.sign;
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be = u.bits.exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1);
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LDBL_TO_ARRAY32(u, bits);
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switch (fpclassify(u.e)) {
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case FP_NORMAL:
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kind = STRTOG_Normal;
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#ifdef LDBL_IMPLICIT_NBIT
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bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32);
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#endif /* LDBL_IMPLICIT_NBIT */
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break;
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case FP_ZERO:
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kind = STRTOG_Zero;
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break;
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case FP_SUBNORMAL:
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kind = STRTOG_Denormal;
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be++;
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break;
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case FP_INFINITE:
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kind = STRTOG_Infinite;
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break;
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case FP_NAN:
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kind = STRTOG_NaN;
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break;
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default:
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abort();
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}
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ret = gdtoa(&fpi, be, vbits, &kind, mode, ndigits, decpt, rve);
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if (*decpt == -32768)
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*decpt = INT_MAX;
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return ret;
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}
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